Zamana dayalı terahertz ölçüm ve görüntüleme tekniklerinin geliştirilmesi

Altan, Hakan
Berberoğlu, Halil
Technologies and applications based on terahertz (THz) waves are being followed today with great interest. These technologies are shedding light on many applications being researched in todays’ Physics laboratories such as laser optics, material science and ultra fast photonics. Undoubtedly, the most successful of these applications has been in the development of timedomain terahertz spectroscopic and imaging systems which has been utilized in the characterization of dielectrics and semiconductors. This pulsed technique has allowed users to not only characterize the real and imaginary dielectric function of these materials at the same time, but also their dynamical behavior; which given the energy of the terahertz waves (few meV) can be used to study a plethora of energetic events in these systems. In this project first we applied our existing Terahertz measurement systems towards characterizing a wide variety of materials such as organic-inorganic materials, solids-liquids, conductors-dielectrics, as well as plasmas and in doing so we were able to gain expertise in a wide variety of measurement techniques. The technques we developed and the knowledge we have gained has been invaluable to many groups involved in material characterization. Second, we developed methods to not only analyze samples in one dimension but in all three dimensions. And lastly, we developed novel systems that measure the dynamical response of samples at these wavelengths after photoexcitation. Developed in all but a few countries in the world, we were able to establish this measurement technique in our own country. The systems and measurement technques we developed as a result of this project has benefited many reserachers. The results we have achieved in order:  Discern and explain differences between diesel and regular unleaded gas  Determine the effect and amount of additives such as ethanol in gas  Concnetration based measurements of tryptophan using novel methods  Understanding increase in structural strength of polymers after plasma treatments  Observing that discharge lamps can detect THz waves  Understanding the response of semiconductors after photoexcitation  Examiming the potential for three dimensional imaging of teeth and skin  Understanding which parameters effect the THz transmission through waveguides based on periodic structures